The present invention relates to chain rotating assemblies, and, more specifically to chain rotating assemblies for agricultural feeders.
An agricultural harvester known as a “combine” is historically termed such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating and cleaning. A combine includes a header which removes the crop from a field, and a feeder which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves and performs a threshing operation on the crop to remove the grain. Once the grain is threshed it falls through perforations in the concaves onto a grain pan. From the grain pan the grain is cleaned using a cleaning system, and is then transported to a grain tank onboard the combine. A cleaning fan blows air through the sieves to discharge chaff and other debris toward the rear of the combine. Non-grain crop material such as straw from the threshing section proceeds through a residue system, which may utilize a straw chopper to process the non-grain material and direct it out the rear of the combine. When the grain tank becomes full, the combine is positioned adjacent a vehicle into which the grain is to be unloaded, such as a semi-trailer, gravity box, straight truck, or the like; and an unloading system on the combine is actuated to transfer the grain into the vehicle.
More particularly, a rotary threshing or separating system includes one or more rotors which can extend axially (front to rear) or transversely within the body of the combine, and which are partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the rotor within the concave. Coarser non-grain crop material such as stalks and leaves are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop material such as chaff, dust, straw, and other crop residue are discharged through the concaves and fall onto a grain pan where they are transported to a cleaning system. Alternatively, the grain and finer non-grain crop material may also fall directly onto the cleaning system itself.
A cleaning system further separates the grain from non-grain crop material, and typically includes a fan directing an airflow stream upwardly and rearwardly through vertically arranged sieves which oscillate in a fore and aft manner. The airflow stream lifts and carries the lighter non-grain crop material towards the rear end of the combine for discharge to the field. Clean grain, being heavier, and larger pieces of non-grain crop material, which are not carried away by the airflow stream, fall onto a surface of an upper sieve (also known as a chaffer sieve) where some or all of the clean grain passes through to a lower sieve (also known as a cleaning sieve). Grain and non-grain crop material remaining on the upper and lower sieves are physically separated by the reciprocating action of the sieves as the material moves rearwardly. Any grain and/or non-grain crop material remaining on the top surface of the upper sieve are discharged at the rear of the combine. Grain falling through the lower sieve lands on a bottom pan of the cleaning system, where it is conveyed forwardly toward a clean grain auger.
The clean grain auger conveys the grain to a grain tank for temporary storage. The grain accumulates to the point where the grain tank is full and is discharged to an adjacent vehicle such as a semi-trailer, gravity box, straight truck or the like by an unloading system on the combine that is actuated to transfer grain into the vehicle.
Agricultural feeders can include a chain engaged with teeth of a sprocket mounted on a rotating shaft. As the shaft rotates, the sprocket also rotates and the teeth of the sprocket engaged with the chain cause rotation of the chain. The chain can engage the teeth of two sprockets to form an endless chain between the two sprockets, with the portion of the chain between the two sprockets moving in a linear, rather than rotational, direction. Paddles or other types of conveying elements can be driven by the chain and contact crop material to convey the crop material in the linear direction before rotating about the sprockets at each end of the endless chain to switch linear direction movement. This allows rotational movement of the shaft to continuously drive the chain and connected conveying elements to linearly move crop material across the feeder.
One particular problem with current constructions is that fed material or debris can become wrapped, impacted or accumulated on the sprockets or shaft rotating the sprockets, as well as under the chain. Material that accumulates on the shaft and/or sprocket can cause friction, requiring more power to rotate the shaft. Further, when material accumulates under the chain during rotation, the effective diameter of the chain can be increased such that the teeth of the sprockets do not engage every link in the chain as the chain is driven by the sprockets. Such an occurrence of the chain skipping one or more teeth of the sprockets is referred to as “chain jumping,” and has been found to significantly reduce the durability of the chain.
What is needed in the art is a feeder that is less prone to adverse effects caused by material and debris wrapping, impacting, and/or accumulating on the sprockets, the shaft rotating the sprockets, and/or the chain being rotated by the sprockets.